A screened hybrid density functional study on energetic complexes: Alkaline-earth metal carbohydrazide perchlorates

The molecular geometries, electronic structures and stabilities of a series of alkaline-earth metal carbohydrazide perchlorates were investigated using the Heyd-Scuseria-Ernzerhof (HSE) screened hybrid density functional. The results show that Be and Mg complexes have six-coordinated octahedron features, as previously reported for the transition metal complexes. However, Ca, Sr and Ba complexes have additional coordinated oxygen atoms from the perchlorate ion. Detailed NBO analyses indicate that the metal-ligand interactions are essentially ionic and play an important role in the stabilities of these energetic complexes. The donor-acceptor interactions result in a reduction of occupancies of sigma(C-O) and sigma(N-H) bond orbitals, and also their subsequent impact on bond length and bond order. (C) 2009 Elsevier B.V. All rights reserved.